Wire rod and wire are ordinarily drawn into final products matched to the purpose of use. Before conducting the drawing process, however, it is necessary to put the wire rod or wire in a condition for drawing.
In the case of high-carbon steel wire rod or wire, the prior art requires that a mixed texture of uniform, fine pearlite and a small amount of pro-eutectoid ferrite be established before drawing, and, therefore, a special wire rod or wire heat treatment called "patenting" is conducted. This treatment heats the wire rod or wire to the austenite formation temperature and then cools it at an appropriate cooling rate to complete pearlite transformation, thereby establishing a mixed texture of fine pearlite and a small amount of pro-eutectoid ferrite.
In the wire rod production method of Japanese Patent Publication No. Sho 60-56215, a heat treatment is conducted for obtaining a mixed texture of fine pearlite and a small amount of pro-eutectoid ferrite by immersing the wire rod heated to the austenite formation temperature in molten salt and then cooling it from 800.degree.-600.degree. C. at a cooling rate of 15.degree.-100.degree. C./sec.
However, pearlite texture involves the problems of ductility degradation during drawing at a high reduction of area and of cracking in twist test (hereinafter referred to as "delamination").
The object of this invention is to provide bainite wire rod or wire excellent in ductility and not giving rise to the foregoing problems during drawing, and to provide methods of producing the same.